Esterification eliminates water Steps:

• Ester forms via RCOOH + R'OH → RCOOR' + H₂O.
• Carbon atoms: All carbons from acid (R + C + OOH) and alcohol (R' + OH) transfer to ester; none lost.
• Hydrogen atoms: Water removes 2H (1 from acid's OH, 1 from alcohol's OH).
• Oxygen atoms: Water removes 1O (from acid's OH).

Why C is correct:

• Esterification reaction (RCOOH + R'OH → RCOOR' + H₂O) conserves all C atoms but subtracts 2H and 1O in H₂O.

Why the others are wrong:

• A: No carbon atoms lost; all preserved in ester.
• B: Oxygen atoms decrease by 1; not the same.
• D: Hydrogen and oxygen atoms decrease; not the same.

Final answer: C